docs: sysctl/fs: remove references to super-max/-nr

These were removed in 2.4.7.8. Remove references to super-max and
super-nr in the sysctl documentation.
Signed-off-by: Stephen Kitt <steve@sk2.org>
Link: https://lore.kernel.org/r/20220930102937.135841-5-steve@sk2.orgSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/admin-guide/sysctl/fs.rst

@@ -277,16 +277,6 @@ or otherwise protected/tainted binaries. The modes are
 =   ==========  ===============================================================
 
 
-super-max & super-nr
---------------------
-
-These numbers control the maximum number of superblocks, and
-thus the maximum number of mounted filesystems the kernel
-can have. You only need to increase super-max if you need to
-mount more filesystems than the current value in super-max
-allows you to.
-
-
 mount-max
 ---------